Userscript

A userscript or user script is a script ran in a web browser, enabled by a browser extension, to alter the way a website is displayed or used. Userscripts are usually written in JavaScript.

To manage all of the installed userscripts, a userscript manager such as Tampermonkey and Greasemonkey can be installed as a browser extension.

Internet terms, Tampermonkey, User, Web design terms